A356546 → x ↦ x+1 → reverse

nonnegative coefficientsonly rational roots

Proved for all n all roots real, in (−∞, 0]coefficients of one signHadamard kernel

Recurrence

\(\left(n\right)\,P_{n}(x) = \left(-2 - 4\,x + 4\,n + 8\,n x\right)\,P_{n-1}(x)\)
\(P_{0}(x) = 1\)

Rows ?

nx0x1x2x3x4x5x6x7x8x9x10x11x12x13x14Pn(1)
011
1246
26242454
320120240160540
4705601680224011205670
52522520100802016020160806461236
6924110885544014784022176017740859136673596
73432480482882889609601921920230630415375364392967505784
8128702059201441440576576014414400230630402306304013178880329472084440070
9486208751607001280326726409801792019603584026138112022404096011202048024893440956987460
10184756369512033256080177365760620780160148987238424831206402837852160212838912094595072018919014410909657044
11705432155195041551950409311702403724680960104291066882085821337629797447680297974476801986496512079459860481444724736124965162504
122704156648997447138971844759314560214169155206853412966415991296921627413651865634267064832030459613184018275767910466457337856110762229761437099368796
13104006002704156003244987200237965728001189828640004283383104001142235494400228447098880034267064832003807451648000304596131840016614334464005538111488008520171520016581915793800
1440116600112326480014602442400116819539200642507465600257002986240077100895872001762306191360030840358348800411204777984004112047779840029905802035200149529010176004600892620800657270374400191876454185400
Technical details
Node id
n-24e260a0c0fb324c · revision 0 · JSON
Definition source
derived:reversal
Fingerprint
f6-11aec07ce60b6d61

Observed on the stored rows ?

  • Degrees: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14 (affine: slope 1, intercept 0)
  • Palindromic rows: no
  • γ-positive (gamma_positive): no
  • Nonnegative coefficients (nonn): yes
  • Only rational roots (rr_by_factors: every nonzero row is a product of linear factors over ℚ): yes

Matches ?

No OEIS matches.

Submission text ?

Atlas rows n = 0, …, ascending powers of x
%e Example
Triangle begins:
  0:     1;
  1:     2,      4;
  2:     6,     24,      24;
  3:    20,    120,     240,      160;
  4:    70,    560,    1680,     2240,     1120;
  5:   252,   2520,   10080,    20160,    20160,      8064;
  6:   924,  11088,   55440,   147840,   221760,    177408,     59136;
  7:  3432,  48048,  288288,   960960,  1921920,   2306304,   1537536,    439296;
  8: 12870, 205920, 1441440,  5765760, 14414400,  23063040,  23063040,  13178880,   3294720;
  9: 48620, 875160, 7001280, 32672640, 98017920, 196035840, 261381120, 224040960, 112020480, 24893440;
%F Formula
The row polynomials satisfy n*P(n,x) = (4*n-2+(8*n-4)*x)*P(n-1,x) for n >= 1, with P(0,x) = 1.
%t Mathematica
P[0, x_] := 1;
P[n_, x_] := P[n, x] = Expand[Together[((4*n - 2 + (8*n - 4)*x)*P[n - 1, x])/(n)]];
Table[CoefficientList[P[n, x], x], {n, 0, 9}] // Flatten
%o PARI/GP
P(N) = {my(v = vector(N + 1)); v[1] = 1; for(n = 1, N, my(i = n + 1); v[i] = ((4*n - 2 + (8*n - 4)*x)*v[i - 1])/(n)); v};
row(n, p) = {my(c = Vecrev(p)); c};
T(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};
T(9)

polytool c48629374597

Properties

Proof chains ? JSON

Candidate equalities ?

Same fingerprint ?

References

  1. [Bra06] Petter Brändén. On linear transformations preserving the Pólya frequency property. Transactions of the American Mathematical Society, 358(8):3697–3716, February 2006. doi:10.1090/s0002-9947-06-03856-6
  2. [Bra15] Petter Brändén. Unimodality, log-concavity, real-rootedness and beyond. Handbook of enumerative combinatorics, :437–483, March 2015. doi:10.1201/b18255-10
  3. [LW07] Lily L. Liu and Yi Wang. A unified approach to polynomial sequences with only real zeros. Advances in Applied Mathematics, 38(4):542–560, May 2007. doi:10.1016/j.aam.2006.02.003
  4. [SP14] J Schur and G Polya. Über zwei Arten von Faktorenfolgen in der Theorie der algebraischen Gleichungen. J. Reine Angew. Math., 1914.